1. Field of the Invention
The present invention relates to a buckle retractor which, at the time of a sudden deceleration of a vehicle, retracts a buckle toward a lower side of a vehicle body to cause a webbing to be applied closely to an occupant.
2. Description of the Related Art
As means for causing a webbing to be applied closely to an occupant at the time of a sudden deceleration of a vehicle, there has been known, in addition to a webbing retractor, a mechanical buckle retractor, called an inner pretensioner, which retracts, toward a lower side of a vehicle body, a buckle engaged with a tongue plate which is mounted at an intermediate portion of the webbing.
One example of this type of buckle retractor is shown in FIG. 4. In a buckle retractor 70 shown in FIG. 4, a lock plate 76 is connected to an anchor portion 74 of a buckle 72. One end of a wire 80 is mounted at a lower end portion of the lock plate 76 via a connecting piece 78. An intermediate portion of the wire 80 is wound around a pulley 82 provided at a front side of a direction in which the buckle 72 is retracted, and the other end of the wire 80 is connected to a piston 86 disposed within a cylinder 84. The cylinder 84 is equipped with a gas generator 88 which operates at the time of a sudden deceleration of a vehicle so as to generate a large amount of gas. As a result, the piston 86 moves within the cylinder 84 and applies tension to the wire 80, so that the wire 80 is forcibly pull in and the lock plate 76 is retracted together with the buckle 72.
However, in the conventional buckle retractor 70 as described above, since the buckle 72 is retracted via the wire 80, there is needed for a moving stroke of the piston 86 which is the same length as the amount by which the buckle 72 is retracted. For this reason, the size of the cylinder 84 becomes large so that a large configuration space is required. Particularly, there exist drawbacks in that, in a small-size vehicle or the like, in which it is difficult to widely maintain a configuration space, assembling efficiency deteriorates.
The present invention was developed in light of the above circumstances and it is an object of the present invention is to provide a buckle retractor which can sufficiently maintain a space for the amount by which the buckle is retracted and which is of a small size so that a large configuration space is not required.